This invention relates to improvements in membrane configurations for air supported structures.
The majority of air supported structures presently in use include a single membrane envelope which has been fabricated from commercially available high strength industrial fabric, providing a low cost portable or semi-permanent enclosure which is adequately serviceable under conditions where temporary collapse due to accidental damage or vandalism would not be of serious consequence; where heat flow through the membrane is of no major concern in terms of heat gain and/or loss; and/or where sound and light radiation and/or absorbing qualities are not of any particular consequence.
Such previously provided air supported structures are generally fabricated as single skin, evenly stressed envelopes, having a wall comprising a very thin membrane, and in which the fabric of the membrane is a relatively good conductor of heat and is translucent to solar radiation. The same have also been historically extremely poor in sound characteristics, the generally highly stressed and evenly contoured single membrane thereof comprising a reflector of sound waves somewhat akin to the sound reflected from a drum head, frequently producing sound concentrations at various points in the interior of the structure and a "whispering wall" effect in which the sound produced at one point along the perimeter thereof travels thereabout and is magnified in a manner so that it is louder at a point as much as 200 to 300 feet away than at its origin.
It is obvious that lighting fixtures cannot ordinarily be mounted on the walls of an air supported structure, but must be placed around the perimeter of the structure. Thus, air supported structures are generally indirectly lighted by way of ground supported light fixtures which are focused to project light rays against the membrane for reflection from the surface thereof and onto the floor of the air supported structure. Previously provided air supported structures have generally had very poor lighting characteristics, the uniform interior surface of the envelope thereof being highly reflective, concentrating the light at some areas of the floor while leaving other areas very poorly lighted.
Also, since previously provided air supported structures were generally constructed to provide a low cost temporary enclosure, very little attention was given to designing the same for long term structural integrity and weather resistance.
The primary object of this invention is the provision of a membrane configuration which is specifically constructed for use as a wall portion of an air supported structure, the same being designed to provide an air supported structure having long term structural integrity and weather resistance, with predetermined heat flow properties and sound and light radiation and/or absorbing characteristics according to the intended use thereof.
In some instances it may prove desirable to provide a multiple membrane wall for the air supported structure. It is accordingly a further object of this invention to provide air supported structures which may be selectively of single and multiple membrane configurations having the desired total design characteristics.
Other objects and advantages of the invention will become apparent from the following detailed description, taken in connection with the accompanying drawings, and in which drawings: